Coercion uses [base::as.Date()], so time-of-day and timezone information are
dropped. For `POSIXct` inputs, the date is computed by `as.Date.POSIXct`
(which uses `tz = "UTC"` by default). Be aware that ambiguous character
dates (e.g., `"01/02/2024"`) depend on your R locale/format unless you
specify a format before calling this function.